1. Field of the Invention
This invention relates to internal support frames, and more particularly to internal support frames within snowboards.
2. Description of Related Art
Snowboards are a recreational device. Snowboards provide a platform on which a person places both feet. Typically, a person would use a snowboard to slide down a hill, such as a conventional ski slope, in a fashion which is similar to surfing ocean waves on a surfboard. Each foot of the user is typically placed into a snowboard boot. The snowboard boot is held in place by a binding mounted on the snowboard. By a shifting of the user's weight, the snowboard can be controlled to turn to the right or left. Metallic edges, similar to the edges of conventional skis, provide added control.
One of the problems faced by the manufacturers of snowboards is making a snowboard that is flexible enough to allow the user to maintain good control at relatively slow speed. However, a snowboard must also remain stable at relatively high speeds over rough terrain, such as might be encountered on a conventional ski slope. Vibrations at the nose and tail of the snowboard can make it difficult to control the snowboard by reducing the contact between the snowboard and the terrain. In addition, a snowboard must be very durable. In particular, the edges which are primarily responsible for controlling the direction of the snowboard, make intermittent contact with the terrain. A number of techniques have been taught to provide appropriate flexibility, durability, and stability in manufacturing skis. For example, U.S. Pat. No. 4,556,237, issued to Meatto, et al. discloses selectively reinforcing an alpine ski. FIG. 1 is an illustration of the Meatto reinforcement system. In Meatto, a ski is reinforced with high strength fiber reinforcing rods 24 positioned generally horizontally within the ski's cross-section. The rods are discontinuous in the area of a binding plate 16. The rods 24 extend from near a shovel end 13 of the binding plate 16 to a shovel contact point 32 at one end of the ski, and from near a tail end 17 of the binding plate 16 to a tail contact point 34 at the other end of the ski. These contact points 32, 34 are the lines of contact of the ski where the shovel and tail of the ski under the force of only its own weight touch a flat surface. The rods 24 increase the overall resistance to flexural deformation of the structure of the ski 10 by selectively increasing the flexural or bending strength when compared to a cross-sectional beam of equivalent stiffness without such reinforcing rods 24.
However, snowboards differ from skis in that the both feet are placed on a snowboard, whereas only one foot is placed on a skis. Accordingly, the forces applied to snowboards differ from the forces applied to skis. For example, the user of a snowboard may, with a rear foot, apply a torque in one direction to the rear portion of the snowboard while applying a torque to a front of the snowboard in the opposite direction with the front foot. Clearly, the fact that two feet independently control the snowboard is an advantage. Therefore, it would be advantageous to design a snowboard such that the snowboard responds most favorably to the forces applied by each foot without sacrificing stability.
Prior art reinforcement systems in the context of skis, such as taught by Meatto, provide additional structural reinforcement to aid in dampening vibrations. But such reinforcing rods do not provide additional controlled resistance to torques exerted by twisting forces such are those encountered in the context of a snowboard in which two feet are used to control the snowboard. Since snowboards are subject to such torques, there is a need for a support structure that is capable of dampening vibrations of the front and rear of the snowboard, adding structural integrity to the snowboard against structural failures due to torques applied from the front to the rear, and to allow the front and the rear of the snowboard to be twisted about the central longitudinal axis in a controlled manner to allow maximum control of the snowboard during use.